The present invention pertains to portable exercise devices and specifically to portable devices for simultaneous isotonic and isometric exercise of major body muscle groups.
Interest in physical fitness and conditioning activities has increased dramatically in recent years. A particular emphasis has developed on portable exercise equipment which would allow the user to engage in fitness exercises almost anywhere. Examples of such devices are described in U.S. Pat. Nos. 4,580,778; 4,290,600; 4,290,599; 4,239,212; 4,211,405; 3,971,255; 3,834,697; and 3,746,339.
Unfortunately, the prior art portable exercise devices are subject to a number of deficiencies. Many are too bulky and heavy to be considered truly portable. Others are too complicated, requiring a complex assembly of springs and related components. Some, because of the use of springs as the primary tension device, do not provide a constant resistance to effort to the user over the full range of motion of the device. Most of the previously known exercise devices are not easily adjustable in terms of required effort, nor do they provide a simple means of alerting the user that inadequate force is being applied to achieve optimum fitness benefits. Finally, the prior art portable exercise devices do not allow the user to simultaneously engage in isotonic and isometric exercises.
What is needed, then, is a portable exercise device which is compact and lightweight, which is simple in construction, adjustment, and operation, which alerts the user when inadequate effort is being employed, and which allows for both isotonic and isometric exercise of major muscles of the body.